This application relates in general to a method, apparatus, and article of manufacture for providing high-speed digital communications through a communications channel, and more particularly to a method, apparatus, and article of manufacture for providing slicer level adaption for a high-speed digital communications system.
Digital communications systems are continuously increasing the transfer rate at which data is transmitted between devices through a communications channel, for example, a backplane. One technique for increasing the data transfer rate is to encode the data prior to transmission. In this regard, there are a number of techniques for encoding data. Many of these techniques utilize different numbers of signals and modulation of symbols in order to increase the data transfer rate. One such method of modulating symbols is to use a multi-level pulse amplitude modulation (PAM-n) scheme that encodes a plurality of bits of data into or onto a single signal in which the symbols are represented as a set of signal levels between minimum and maximum signal levels.
In order to properly decode the received signal to thereby recover the digital representation of the data bits being transmitted, signal levels need to be set between the minimum and maximum signal levels that allow the transmitted symbol to be decoded properly. These are typically referred to as slicer levels.
In conventional systems, the slicer levels are an equal distance between adjacent signal levels. These levels are typically set during system design. As such, each signal level has an equal weight and is fixed. This slicer level scheme, however, may not provide a sufficient result from the perspective of a bit error rate of the system performance.
Accordingly, there exists a need to increase the performance of channel communications by, for example, providing a system and technique that includes an improved slicer level adjustment mechanism and technique.